Back brush



FIG. 1 is top plan view a back brush showing my new design.

FIG. 2 is a right side elevation view thereof.

FIG. 3 is a rear elevation view thereof.

FIG. 4 is a front elevation view thereof.

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a left side elevation view thereof.

In the drawings, the broken lines depict environmental subject matter only that forms no part of the claim. 

CLAIM The ornamental design for a back brush, as shown and described. 